P0174 Code -Solutions based on symptoms

Question

2005 Dodge Magnum, 3.5L auto. Running fine when parked. Now not too difficult to start but when it does it runs extremely rough for only seconds then dies. If you try to keep it going it will rev out to 300 then die, and smoke, most likely unburned engine emissions. Check engine light is flashing and diagnostic screen on dash says 0174 lean cyl Bank 2 only. No other codes. Something serious or minor but confusing the computer